In May 2015, Joshua Vallum brutally murdered his ex-girlfriend, Mercedes Williamson, for fear of others learning that she was transgender. Two years later, 29-year-old Vallum has been sentenced to 49 years in prison for a federal hate crime targeting a transgender woman.

CNN reports that Vallum was aware of Williamson’s identity when he began dating the teenager; however, he concealed this information. Although the couple broke up in 2014, Vallum later decided to kill the 17-year-old in 2015, after one of his friends learned that she was transgender. A resident of Lucedale, Mississippi, Vallum belonged to the Almighty Latin Kings and Queens Nation crime gang and believed he might be punished for his relationship with Williamson.

The murder was an especially horrifying one: after convincing her to get into his car, Vallum bludgeoned and stabbed Williamson as she attempted to escape. Initially, Vallum claimed that he killed his ex-girlfriend in a panicked frenzy upon learning that she was transgender. But on December 21, 2016, he admitted that this statement was false—and that he would not have killed Williamson if she were not a trans woman.

Upon pleading guilty, Vallum was sentenced to life in prison. The federal government was able to designate the murder as a hate crime because Mississippi has not implemented protections for those who commit crimes motivated by gender bias. Vallum is in fact the first person to be prosecuted for a specifically transphobic federal hate crime. He has also been fined $20,000.